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COMMON AUDIO
REJECTION ISSUES

This is a list of the most common quality control issues found in audio. Submissions may fail for reasons not stated below, and reasons for failure are subject to change. Please share with your production teams to ensure spec requirements are met and to avoid content resubmission.

Codec/Container

  • The AAC audio codec is NOT supported. Audio must be delivered as uncompressed Linear PCM

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​Sample Rate/Bit Depth

  • Audio with a sample rate of 44.1kHz is NOT supported. It must be 48kHz.

  • Audio bit depth must be 16-bit or 24-bit. A 32-bit “float” rate is not acceptable. 

  • Poor audio/video sync is not acceptable. Audio/video must be properly SYNCED on all content.

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Audio Compression

  • Audio must not contain artifacts consistent with lossy compression being introduced into the processing workflow. All submissions must be encoded from the best quality master possible.

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Audio Configuration

  • Two Discrete Tracks

    • This Auto-QC failure indicates that the submitted asset contains two discrete Tracks of audio, with 1 Channel on each Track. Per our Video Servicing Asset Spec, all audio must be delivered as a 2 Channel Stereo Pair contained on 1 audio Track. ​

    • NOTE: This failure does not indicate whether or not the underlying audio content is Dual Mono or Stereo. The audio content will need to be reviewed via audio tools as outlined in the "Dual Mono" section below to determine if the audio is Stereo and can be re-configured to meet our specs. 

  • Multichannel​

    • This Auto-QC failure indicates that the submitted asset contains more than 2 audio Channels, regardless of the number of audio Tracks. Per our Video Servicing Asset Spec, all audio must be delivered as a 2 Channel Stereo Pair contained on 1 audio Track.

    • NOTE: This failure does not indicate whether or not the underlying audio content is Dual Mono or Stereo. The audio content will need to be reviewed via audio tools as outlined in the "Dual Mono" section below to determine if there is Stereo audio on any of the tracks that can be re-configured to meet our specs. 

  • ​Single Channel Mono​

    • This Auto-QC failure indicates that the submitted asset contains 1 audio Track containing 1 audio Channel. Per our Video Servicing Asset Spec, all audio must be delivered as a 2 Channel Stereo Pair contained on 1 Track.

  • ​Unsupported Channel Tagging​

    • This Auto-QC failure indicates that the submitted asset contains audio channels that are not properly assigned. Per our Video Servicing Asset Spec, channel 1 must be assigned "Left" and channel 2 must be assigned "Right" in the Stereo Pair. 

 

Dual Mono Audio

  • If both the L and R audio Channels are identical, it is DUAL CHANNEL MONO and will fail. Audio must be in STEREO and in phase.

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Dual Mono occurs when both the Left and Right Channels are identical to one another.

Audio must be checked on an audiometer as QuickTime will falsely define anything with 2 Channels as “stereo.”

 

DUAL MONO                                                     STEREO    

 

 

 

 

 

 

 

 

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Wave Form is a straight vertical line               Wave Form branches out to left and right

 

Right and Left Levels are uniform                        Right and Left Levels are dynamic

 

            Correlation Meter is static at +1               Correlation Meter is dynamic between 0 and +1

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dualmono_edited.jpg

MONO vs STEREO AUDIO (TROUBLESHOOTING)

 

Issues related to Mono / Dual Mono versus True Stereo mixes may be a result of master audio originating as Mono, audio clip/audio tracks configurations, and/or export settings in an edit timeline. The explanations and figures below serve as general criteria one can reference in either Adobe Premiere or DaVinci Resolve to remediate audio rejections with Video Services.

 

If the engineer is still having trouble passing the Dual Mono check of Video Service's Auto QC process but has determined that the source audio is indeed True Stereo, please ‘reply all’ to the AQC e-mail and escalate with Video Services.

 

Initial Steps Post-Video Services Auto QC Rejection

 

  1. ​Can the source audio be confirmed as Mono or Stereo?

    • If the source is Mono, further information will be needed from the Label/Territory for Videos Services to proceed.

    • If the source is True Stereo, but the export is rejected as Mono, it is highly likely that the audio engineer or video editor has improper audio configurations and/or exporting settings within the editing platform.

  2. Confirm audio configuration and exporting settings within the applicable NLE.

    • If the editing platform is Premiere or Resolve, reference the below images and setup instructions. Otherwise, notify Video Services and we will advise on next steps.

  3. If upon confirmation of settings and re-export of materials, the updated asset is still mono, the Label/Territory uploader will need to work with Video Services engineers to advise on next steps.

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Confirming Source Audio

 

Before checking the file audio configuration or export settings, confirm the source audio is Mono, Dual Mono or True Stereo, and whether or not the output submitted is different than this.

 

To begin, the engineer/uploader should open the asset in his or her editing platform and check the audiometer as the file plays. For a visual representation of the differences between Dual Mono and Stereo audio, reference the illustration below (Figure 1), as depicted in Premiere’s audiometer.

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With Stereo audio the L and R Channels bounce independently (see below, right). With Dual Mono, the L and R Channels are identical during playback (see below, middle), bouncing simultaneously. 

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mono-dual-stereo.jpg

After reviewing with an audiometer, if the asset is confirmed as Mono / Dual Mono, the uploader was likely provided a Mono source. In this case, the audio should be re-supplied in True Stereo (if applicable) or the Label/Territory will need to provide clarification on why Mono is the best available source.

 

Alternatively, if the source audio is confirmed as True Stereo, but the submitted output to Video Services is Dual Mono, then an audio configuration or export setting error has likely occurred and needs to be fixed before resubmission.

 

Important: If the sequence/clip settings or source audio are set to / originate as Mono, but your export settings are Stereo, the file output will still be Dual Mono, regardless of what you set on export. Please keep this in mind when reviewing your source and configurations on any editing platform. 

 

PREMIERE

 

1. The Clip Settings within the Project panel. Project Panel ➡  rt. click selected clip for export ➡ Modify ➡ Audio Channels.

Premier 1.png

    a. Once in the Audio Channels configuration, confirm audio is set to Stereo.

Premier a..png

2. In the Audio Track Mixer, confirm the Master audio track and all tracks containing music are configured for Stereo. Below is a common track layout that is shown configured properly to maintain a True Stereo output. Notice that there are two yellow lines at the bottom of each audio meter, which indicates each track is configured for Stereo.

Premier 2..png

RESOLVE

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1. Navigate to the Clip Attributes within the Media Pool panel. Media Pool ➡ rt. click selected clip for export ➡ Clip Attributes…. ➡ Audio tab.

Reslove 1.png

    a. Once in the Audio Channels configuration, confirm audio is set to Stereo.

Reslove a.png

2. In the Audio Mixer, confirm the Main audio track and all tracks containing music are configured for Stereo. Below is a common track layout that is shown configured properly to maintain a True Stereo output. Notice that there are two thin columns within each audio meter, which indicates all tracks are configured for Stereo.

Resolve 2.png
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